From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933086AbcCGXQZ (ORCPT ); Mon, 7 Mar 2016 18:16:25 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:39720 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754132AbcCGWzl (ORCPT ); Mon, 7 Mar 2016 17:55:41 -0500 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Eric Dumazet , "David S . Miller" , Kamal Mostafa Subject: [PATCH 4.2.y-ckt 232/273] ipv6: fix a lockdep splat Date: Mon, 7 Mar 2016 14:50:23 -0800 Message-Id: <1457391064-6660-233-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 2.7.0 In-Reply-To: <1457391064-6660-1-git-send-email-kamal@canonical.com> References: <1457391064-6660-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 4.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.2.8-ckt5 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ From: Eric Dumazet [ Upstream commit 44c3d0c1c0a880354e9de5d94175742e2c7c9683 ] Silence lockdep false positive about rcu_dereference() being used in the wrong context. First one should use rcu_dereference_protected() as we own the spinlock. Second one should be a normal assignation, as no barrier is needed. Fixes: 18367681a10bd ("ipv6 flowlabel: Convert np->ipv6_fl_list to RCU.") Reported-by: Dave Jones Signed-off-by: Eric Dumazet Acked-by: Hannes Frederic Sowa Signed-off-by: David S. Miller Signed-off-by: Kamal Mostafa --- net/ipv6/ip6_flowlabel.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/net/ipv6/ip6_flowlabel.c b/net/ipv6/ip6_flowlabel.c index 1f9ebe3..dc2db4f 100644 --- a/net/ipv6/ip6_flowlabel.c +++ b/net/ipv6/ip6_flowlabel.c @@ -540,12 +540,13 @@ int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen) } spin_lock_bh(&ip6_sk_fl_lock); for (sflp = &np->ipv6_fl_list; - (sfl = rcu_dereference(*sflp)) != NULL; + (sfl = rcu_dereference_protected(*sflp, + lockdep_is_held(&ip6_sk_fl_lock))) != NULL; sflp = &sfl->next) { if (sfl->fl->label == freq.flr_label) { if (freq.flr_label == (np->flow_label&IPV6_FLOWLABEL_MASK)) np->flow_label &= ~IPV6_FLOWLABEL_MASK; - *sflp = rcu_dereference(sfl->next); + *sflp = sfl->next; spin_unlock_bh(&ip6_sk_fl_lock); fl_release(sfl->fl); kfree_rcu(sfl, rcu); -- 2.7.0